so how does an american flyer locomotive work?

That’s a great question! The postwar American Flyer S gauge locomotives (by A.C. Gilbert, late 1940s–1960s) are clever little machines that mix simple mechanical engineering with rugged AC electric motors. Here’s an overview of how they work, broken down into their main systems:

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🔌 Power & Electrical Pickup

• Track Power: Flyer used a two-rail S gauge track (unlike Lionel’s 3-rail O gauge). Each rail carries one side of the AC power (about 15–18 volts AC from a transformer).
• Pickups: The locomotive wheels on one side connect to one rail, and the other side connects through pickup shoes or rollers that rub the opposite rail. This completes the circuit.
  
  

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⚡ Motor

• Most postwar locomotives used an open-frame AC universal motor.
• Key components:
  • Armature: A rotating coil of wire that creates a magnetic field when current flows.
  • Field coil: Stationary electromagnet that interacts with the armature.
  • Brushes & commutator: Carbon brushes press on a segmented copper commutator, switching current direction in the armature coils so the motor keeps spinning.
• Because it’s a universal motor, it can run on AC or DC power directly.

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🔄 Direction Control (“E-Unit”)

• Gilbert locomotives usually had an automatic reversing unit (similar to Lionel’s E-Unit).
• Inside is a rotating drum and pawl mechanism, stepped each time power is interrupted.
• Each cycle changes the motor wiring:
  • Forward → Neutral → Reverse → Neutral → Forward …
• That’s why when you flick the transformer off and back on, the locomotive often changes direction.

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⚙️ Drive Train

• The motor turns a worm gear or pinion gear, which drives the axle gears.
• Most engines had all-metal gearing (durable, but they need occasional lubrication).
• Depending on the model:
  • Steam locos had rods and valve gear linked to the drivers for realism.
  • Diesels often had two power trucks (motors in both trucks, or one motor geared to both).

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💡 Accessories & Features

• Many postwar Flyer engines had:
  • Smoke units (a heater element vaporizing special fluid or pellets, synchronized with the pistons on some steamers).
  • Operating headlights (simple bulb wired into the motor circuit).
  • Whistle or horn units (operated with a transformer button, usually a small DC relay driving a fan or vibrating reed horn).
  • Chuffing sound (mechanical cam and bellows in some steam engines).

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🛠️ In Practice

So when you set one on the track:

1. You apply AC from the transformer.
2. Power flows through the wheels/pickups → motor.
3. The motor spins, gearing turns the axles, and the train moves.
4. Turn the transformer off → the E-unit steps to the next position.
5. Turn it back on → the train runs in the new direction.